Typical computer devices (e.g., personal computers, mobile phones, tablets, etc.) include graphical user interface (GUI) systems that are optimized for accepting user input from one or more discrete input devices for entering text (such as a keyboard), and a pointing device (such as a mouse) with one or more buttons for activating user selections. Some computing systems have expanded the input systems available to a user by providing a pen-like stylus. For purposes of this disclosure, the term “pen-like stylus,” “stylus” and “pen” may be used interchangeably to describe an active pen (also referred to as active stylus) that may be an input device that includes electronic components and allows users to write directly or interact with the display screen surface of a computer device (e.g., laptops, tablets, mobile devices, etc.).
Using a pressure sensitive overlay or an electronic digitizer, a computer display may be enhanced to accept interaction from a user by using the stylus. The stylus or pen communicate pressure information (e.g., how hard the user has pressed on the screen) to the host through reserved communications windows in the pen/stylus protocol. The pressure information can be useful in applications, for example, painting where the pressure may correspond to the thickness of the line. While the information from the pressure sensor of the stylus can be valuable for the computer device, the pressure sensors are also susceptible to be damaged or breakage because the pressure sensors are generally associated with the stylus tip which itself presents a physical weakness on the stylus as a whole.
However, if the pressure sensor or the stylus tip associated with the pressure sensor is damaged or broken, a user typically is left with no other alternative but to discard the damaged stylus and purchase a new one. This is because in current pen protocols, there is no mechanism for the stylus to report that the stylus is in contact with the computer device without available pressure information. As such, the damaged stylus may be rendered useless because pressure is generally used as an indication of contact with a display or screen.
While one solution may be to possibly revise existing pen protocols to account for the reporting of the pressure-less pen (i.e., damaged pressure sensor), such a solution is not always feasible, especially when a large number of protocol timing windows are already taken by existing data. Revising the existing protocol also does not help existing in-market pen devices which have experienced a broken pressure sensor.